A reinterpretation of the electronic spectrum of pyrrole: a quantum dynamics study.
A reinterpretation of the electronic spectrum of pyrrole: a quantum dynamics study.
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DOI：
10.1063/1.4861223
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发表时间：
2014-01
期刊：
影响因子：
--
通讯作者：
S. Neville;Graham A. Worth
中科院分区：
文献类型：
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作者：
S. Neville;Graham A. Worth
利用MCTDH方法从波包传播中计算出吡咯电子能谱的第一波段。为此，构造了两个模型哈密顿量来描述吡咯的七个低洼激发态。这些哈密顿量基于振动耦合模型，并通过拟合广泛的CASPT2和EOM-CCSD计算来参数化。详细分析了吡咯在5.5 ~ 6.5 eV范围内的电子能谱结构。本文评价了低能级3s和3p里德伯态跃迁到ππ(*)态的强度借用的作用，并对大部分谱进行了重新分配，结果表明谱中的大多数态主要是里德伯态。由此得出的结论突出了基于计算的垂直激发能与电子光谱中观测到的峰值位置匹配的分配的局限性。
The first band in the electronic spectrum of pyrrole is calculated from wavepacket propagations performed using the MCTDH method. To do so, two model Hamiltonians are constructed to describe seven low-lying excited electronic states of pyrrole. These Hamiltonians are based on the vibronic coupling model, and are parameterised via fitting to extensive CASPT2 and EOM-CCSD calculations. A detailed analysis of the structure of pyrrole's electronic spectrum in the range 5.5 to 6.5 eV is made. The role of intensity borrowing from transitions to ππ(*) states by lower-lying 3s and 3p Rydberg states is assessed, and reassignments of much of the spectrum are subsequently made which indicate that most of the states in the spectrum are predominantly Rydberg in character. The resulting conclusions drawn serve to highlight the limitations of assignments based on the matching of calculated vertical excitation energies and the positions of peak maxima observed in electronic spectra.